This project is a multi-disciplinary approach with the goal of identifying the neurobiological basis of behavior changes in the aged. Dr. J. McGaugh and his group are studying the relationship between stress, pain threshold and transmitter systems in the aged. Their recent studies have identified age related changes in opiate receptor activity in various brain areas which appear to correlate with observed behavioral changes. Dr. Marshall and co-workers have continued to investigate sensorimotor disturbances in the aging rodent; most recently examining the pharmacological characteristics of central dopamine systems. Dr. Lynch and co-workers are studying the neurochemical and physiological correlates of long term potentiation. Dr. Cotman and co-workers are continuing their studies on lesion induced synaptic growth in aged brain. It now seems established that new connections for slower and there are fewer following brain injury in aged. Dr. Moldave and co-workers have shown that beta endorphin and enkephalins can inhibit protein synthesis in vitro. Their studies continue to analyze the capacity of aged cells to synthesize proteins.